1. Field of the Invention
The present invention relates to a waterproof tap for use in a connector and, in more particular, to a waterproof tap for a connector used to connect a wire harness which is used to arrange wires in various kinds of electric equipment in the interior of an automobile.
2. Related Art
A connector for a wire harness for arranging wires between various kinds of electric equipment in the interior of an automobile must be waterproof and dustproof in view of its purpose. Therefore, there are various conventional waterproof mechanisms and waterproof structures for this purpose.
For example, a waterproof electric connector disclosed in Japanese Utility Model Publication No. 1-146478 of Heisei, as shown in FIGS. 4 and 5 of the present application, includes a connector housing 31 having a plurality of terminal mounting spaces 30A to 30C, a plurality of receptacle type pressure contact terminals 33 which are respectively connected to the end portions of electric wires and can be stored in the terminal mounting spaces 30A to 30C, a plurality of seal members 34, and a cap 35.
The seal member 34 is an elastic member formed of silicone rubber and includes a plurality of through holes 36A to 36C which respectively extend through the seal member 34 and through which the electric wires 32 can be inserted. Also, the seal member 34 further includes on one surface thereof a plurality of circular recessed portions 38 which are respectively formed along the peripheral edges of the through holes 36A to 36C and also which can be respectively fitted with projecting portions 37 provided in the partition wall end portions of the connector housing 31 defining the terminal mounting spaces 30A to 30C of the connector housing 31. The seal member 34 still further includes on the other face thereof a plurality of fitting recessed portions 40 respectively fittable with projecting portions 39 provided in the cap 35.
The electric wires 32 are inserted sequentially through the cap 35, the through holes 36A to 36C of the seal member 34, and the terminal mounting spaces 30A to 30C of the connector housing 31. The receptacle type pressure contact terminals 33 provided in the end portions of the electric wires 32 are stored in the terminal mounting spaces 30A to 30C of the connector housing 31. The circular recessed portions 38 of the seal member 34 are fitted with the projecting portions 37 of the connector housing 31, and the projecting portions 39 of the cap 35 are fitted into the fitting recessed portions 40 of the seal member 34, thereby completing a waterproof electric connector 41.
According to the waterproof electric connector 41, due to the fact that the circular recessed portions 38 of the seal member 34 are respectively fitted with the projecting portions 37 of the connector housing 31 and also the fitting recessed portions 40 are respectively fitted with the projecting portions 39 of the cap 35, the inner peripheral surfaces 42 of the connector 41 forming the through holes 36A to 36C are respectively deformed inwardly to thereby reduce their respective diameters, with the result that the insulating covered portions of the electric wires 32 are closely contacted with the inner peripheral surfaces 42 to thereby be able to secure a sealed condition between them.
However, in the waterproof electric connector 41 having the above-mentioned structure, when the cap 35 is mounted onto the connector 41, it is not possible to confirm the fitting state between the circular recessed portions 38 of the seal member 34 and the projecting portions 37 of the connector housing 31 and the fitting state between the fitting recessed portions 40 and the projecting portions 39 of the cap 35. Therefore, it is not possible to confirm whether or not the electric wires 32 are in close contact with the through holes 36A to 36C of the seal member 34.
Because the sealing performance of the electric wire 32 depends greatly on the contact state between the inner peripheral surfaces 42 of the seal member 34 and the electric wire 32, if the projecting portions 37 of the connector housing 31 as well as the projecting portions 39 of the cap 35 are not fitted deeply enough into the circular recessed portions 38 of the seal member 34 and the fitting recessed portions 40, then a sufficient pressing force cannot be obtained by means of the inner peripheral surfaces 42 of the seal member 34. This makes it impossible to confirm the fitting state and thus there is a possibility that a sufficient sealing performance is not provided. This is not favorable in controlling the quality of products.
Also, as described above, the method of sealing the electric wires 32 relies on the close fitting between the projecting portions 37 of the connector housing 31 and the circular recessed portions 38 of the seal member 34 as well as the close fitting between the projecting portions 39 of the cap 35 and the fitting recessed portions 40 of the seal member 34. Therefore, to obtain a good sealing performance, it is preferred that these mutually mating components be arranged at mutually corresponding positions. That is, these components must be formed with a relatively high degree of accuracy.
Further, since the seal member 34, as shown in FIG. 5, is arranged such that the circular recessed portions 38 and the fitting recessed portions 40 are so formed as to oppose each other, an operator can carelessly mistake the circular recessed portions 38 for the fitting recessed portions 40 in mounting the seal member 34 onto the connector housing 31. Therefore, it is possible that the seal member may not be mounted correctly to the connector housing. Also, because the seal member 34 is formed of rubber and thus can be easily deformed, it is possible to put the cap 35 on the seal member 34 in such an incorrect mounting condition. As a result of this, there is a possibility that such an incorrectly mounted connector may be used in the wire harness. If this occurs, the expected sealing performance cannot be provided.